1. Field of the Invention:
The invention relates to double skin building construction panels having a foamed-in-place core.
2. Description of the Prior Art:
Double skin construction panels are well known in the prior art for use in the construction of buildings, U.S. Pat. No. 2,284,229. Such double skin panels have utilized thermal-insulation materials such as glass fiber batts, lightweight foamed plastic blocks and the like to maintain the outer sheet in spaced-apart relation. When building panels with spaced-apart facing sheets are applied to a building framework, some means is provided to secure the inner sheet to the framework such as rivets, self-tapping screws, welding, et cetera. The retention of the outer sheet is not always reliable. By providing metal fasteners extending entirely through the outer sheet, the core and the inner sheet, a through-conduction path for thermal transfer results which minimizes the effectiveness of the thermal-insulating properties of the core material. Some double-skin construction panels, e.g., U.S. Pats. Nos. 2,730,210; 3,276,626, provide for the mating of the outer sheet and the inner sheet at the side edges of the panel; this feature provides an objectionable through-conduction path for thermal transfer. Some panels utilize different materials, e.g., relatively low thermal conductivity materials such as polyvinyl chloride, wood, rubber, to serve as side rails for the panels to maintain the inner and outer facing sheets in a relatively rigid, spaced-apart relationship which avoids the high thermal conductivity of metal but does not achieve the exceptionally low thermal conductivity which is desirable, U.S. Pat. No. 3,113,401. In many building panels the outer sheet is maintained in its intended relation by an adhesive film, U.S. Pat. No. 3,235,040. In other panels the outer sheet is auto-adhered to the foamed-in-place panel core. In both of these instances, subsequent weather exposure tends to deteriorate the adhesive bond and thereby to jeopardize the structural integrity of the panel.